Bio-Technology General Corp. announced Tuesday it was issuedpatent No. 5,143,836 directed at plasmid for the production ofcopper-zinc superoxide dismutase (SOD), a naturally occurringenzyme.

The patent is one of two issued to New York, N.Y.,-based BTGthis year covering SOD. The patent is wider in scope thanpatent No 5,112,774 the company was issued in May.

SOD is produced in body tissues to detoxify oxygen-freeradicals (superoxides). Unless these superoxides areneutralized in the body, cells and tissue risk severe damage ifexposed to them.

In mid-1991, Emeryville, Calif.,-based Chiron Corp. filed for aninterference against the patent issued to BTG covering amethod for producing enzymatically active human copper/zincsuperoxide dismutase in bacteria as well as a pendingapplication of its own, claiming an earlier filing date.

According to BTG spokeswoman Leah Berkovits, discussionsbetween BTG and Chiron indicate that the issue will be settledout of court. Berkovits, who would not disclose whether thecompanies had discussed a joint licensing agreement for SOD,said, "Even if Chiron wins the claim, they may have problemscommercializing SOD in the U.S. because other patents we havecovering SOD may create similar problems for them."

Chiron has no SOD clinical trials under way in the U.S. orEurope. It supplies the enzyme for Takeda Chemical Industriesof Japan, which is in Phase III trials using SOD forosteoarthritis. According to Larry Kurtz, Chiron's director forcorporate communications, should Takeda receive marketingapproval for SOD, Chiron will manufacture it for them.

Berkovits said BTG expects to enter U.S. clinical studies withSOD by the end of the year to assess its therapeutic value inthe prevention of bronchopulmonary dysplasia (BPD) inpremature babies in whom oxygen-free radicals destroy lungtissue.

BTG received Orphan Drug designation in 1991 for the enzymeused for BPD. Berkovits says if the application proveseffective, the U.S. patient population could be as high as35,000.

-- Michelle Slade Associate Editor

(c) 1997 American Health Consultants. All rights reserved.